1. Field of the Invention
The present invention is directed toward surgical retractor systems and, more specifically to a retractor stay having an elastomeric band.
2. Description of Related Art
It has proven to be desirable in many surgical procedures to provide means to maintain a surgical incision in an open or exposed condition. Several tissue retraction systems have been developed over the years in response to the need for a means to maintain tissue out of the way of the surgeon. One such system includes a frame or support and a tissue-engaging portion.
One type of conventional frame is a frame made from rigid material with a plurality of notches spaced around the frame. The notches are formed to facilitate attachment of a surgical stay. Example surgical frames of this type are illustrated by U.S. Pat. Nos. 5,785,649, 5,769,783, 4,434,791, 4,430,991, and Re 32,021, the disclosures of which are expressly incorporated herein by reference in their entireties. Additional example frames are disclosed in U.S. patent application Ser. Nos. 09/275,137 filed Mar. 23, 1999, now U.S. Pat. No. 5,951,467, and 29/091,483, filed Jul. 30, 1998, now U.S. Pat. No. D412,576, the disclosures of which are expressly incorporated herein by reference in their entireties and are commonly owned by the assignee of the present application.
Stays for use with such frames are known in the art and generally have a retention hook, a handle and a band. Example stays of this type are illustrated by U.S. Pat. Nos. 5,785,649, 5,769,783, 4,430,991, 3,762,401, and Re 32,021, the disclosures of which are expressly incorporated herein by reference in their entireties. However, these stays suffer from one or more disadvantages. The band of most of these stays is elastomeric and intended to be releasably received by the notches on the frame. The elastomeric bands have either a uniform diameter along their entire length or, as illustrated in FIG. 11, a series of alternating smaller diameter portions and spherically-shaped enlarged diameter sections, or hubs.
The term spherically-shaped hub is not intended to include hub configurations with a concave leading end that engages the frame. Examples of hubs with concave leading edges can be found in U.S. application Ser. Nos. 29/096,289, filed Nov. 9, 1998, now U.S. Pat. No. D414,265, and 29/085,628 filed Mar. 26, 1998, now abandoned, the disclosures of which are expressly incorporated herein by reference in their entireties and are commonly owned by the assignee of the present application.
Elastomeric bands having either a uniform diameter or spherical hubs tend to easily deform and slip through the retractor frame notches, thereby allowing the incision to close. Even though the prior art spherical hubs are larger than the notches in the frame, they tend to slip through the notches since their shapes enable the hubs to leverage themselves through the notch. In addition, the frame and stay tend to become wet during surgery from substances such as blood and irrigation fluid. Although slipping occurs during dry conditions, it occurs with greater frequency during wet conditions since the wetness acts as a lubricant to lower the frictional forces normally retaining the stay in the frame. In addition, many of the prior art stays have handles and bands that contain openings and/or cavities in which blood and debris can collect. Such a stay is not autoclavable or reusable.
It has been found that, depending on the type of tissue and size of the incision, about 0.5 to about 3 pounds of force is required to retract an incision. Under dry conditions, stays having spherical hubs were tested to determine how much force was required to pull the spherical hub through the retractor frame notches. The average force required was 2.78 pounds, with a standard deviation of 0.35. The force required to pull spherical hubs through the frame when wet is even lower.
Other stays have bands made from metal balls held together by metal links protruding through holes formed in the balls. Although metal balls are generally too rigid to pull through frame notches, they are not suitable for autoclaving because debris collects in the holes of the balls. Furthermore, the ball and link type design is less preferred by surgeons who desire the elasticity of elastomeric retractor stay bands. Elastic properties allow the hook and handle of the stay to move with the tissue being retracted as the surgical site moves during the operation. An inelastic stay can easily tear the tissue being retracted. Elastic stays are also easily released from the tissue and frame by stretching the band.
Therefore, there exists a need in the art for an autoclavable, elastic retractor stay that will not inadvertently disengage from or pull through the frame.
There is also a need for a simple to use retractor for resisting the natural tendency of fingers and thumbs to curl during hand and wrist surgery and that does not apply localized pressure to the fingers being restrained. U.S. Pat. No. 3,762,401 discloses a frame having slots through which elastic bands extend. The bands are used to hold the patient's fingers and thumb in place during an operation. However, this arrangement is very cumbersome and difficult to use as bands for each finger must be threaded through the frame, wrapped around each finger, tightened and secured. Other conventional devices for resisting the clenching tendency of fingers have a narrow band or other geometry which have been known to apply localized pressure on the fingers being restrained. This application of localized pressure has the tendency to cause cuts, reduce circulation, and cause other undesirable injury to the patient.